Phytoplankton, microscopic floating plant-like marine organisms (plankton means wanderer) are at the bottom of the marine food chain. They perform photosynthesis using water, carbon dioxide, and sunlight to produce glucose for their own use, as well as oxygen. Humans and all land animals and sea creatures are dependent on phytoplankton. The chlorophyll in phytoplankton can be observed by remote sensing instruments and is used by scientists as a measure of phytoplankton. In this lesson, students will use satellite data to explore and determine the correlation between sea surface temperature, sunlight, and the amount of chlorophyll (phytoplankton) in the Gulf of Maine at various times of year.